The present invention relates to a method for operating an internal combustion engine according to the preamble of patent claim 1.
In the journal xe2x80x98Auto Motor und Sportxe2x80x99, volume 17, 1999, page 49, an electrohydraulic valve actuation system for an internal combustion engine has already been described which includes a tappet actuated by a camshaft that does not act directly on a gas exchange valve. (inlet valve) in the cylinder head of the internal combustion engine but by means of hydraulic oil (motor oil). The pressure of the hydraulic fluid propagates by way of a brake piston to the gas exchange valve, and this quantity of hydraulic oil and, thus, also the stroke of the gas exchange valve in the cylinder head can be varied in response to the valve""s switch position of an electromagnetic valve integrated in the cylinder head. Variations of the valve opening times cannot be ruled out due to manufacturing tolerances for the above-mentioned components so that unequal cylinder fills will automatically lead also to a spreading of the exhaust emissions, especially with respect to the multi-cylinder construction of the internal combustion engine.
In view of the above, an object of the present invention is to develop a method for operating a multi-cylinder internal combustion engine which permits adapting the cylinder fills of all engine cylinders so that the above-mentioned shortcomings are avoided.
According to the present invention, this object is achieved by a method with the features of patent claim 1.